1973 4hp evinrude overheating

[trucker]

i have a 1973 4hp evinrude starts good but gets hot and stops running, I have looked at the inpeller and its good their is water comming out of the exhaust, i am at a loss can anyone shed sone light on this for me.

 

[Paul Moir]

Re: 1973 4hp evinrude overheating

Best to replace the impeller no matter how it looks. You need a new one every few seasons and they're only about $15. Lot cheaper than a new motor.

There are two parallel cooling passages on that engine - perhaps one is blocked. You can tell this is happening because the bypass passage remains cool but the head gets burning hot. The head is normally hot so to tell if it's too hot, dribble a little water onto it. If it sizzles it's too hot.

Have a look at my 4hp site here:
Click here

Click on the picture and it'll expand.

 

[DJ]

Re: 1973 4hp evinrude overheating

I just repaired my fathers 4 horse, for the same issue.

The passages under the powerhead were blocked.

 

[trucker]

Re: 1973 4hp evinrude overheating

thanks that just made my day. I'm pretty sure that I have a blocked water jacket now that I can see how to get at them i can flush them and clean them out and get back on the water.

 

[Paul Moir]

Re: 1973 4hp evinrude overheating

Sometimes it's a little, sometimes it's a lot.

If you're lucky, you can do it by just taking the exhaust cover (flat plate on the side) and head off. But if it's clogged up under the powerhead, then the engine will have to come out. See the rest of my tutorial there to see what's involved in removing the engine.

 

[trucker]

Re: 1973 4hp evinrude overheating

I have already taken off that plate and cleaned out that part of the water jacket. but i didn't know how to get at the rest of it.but now I do. what would you use to clean out the small holes( small wire) ? One more thing, where the lower end connects should there be a gasket?

 

[DJ]

Re: 1973 4hp evinrude overheating

Yes,

There is a gasket between the powerhead and the exhaust tower. John/Rude dealers can still get it.

 

[Paul Moir]

Re: 1973 4hp evinrude overheating

Unless you mean between the lower unit and the midsection. There should be no gasket at all there.

 

[trucker]

Re: 1973 4hp evinrude overheating

well I cleaned out the water jacket and that seemed to do the trick, the spark plugs are still a little hot but now i can touch the side of the motor with out burning my fingers. I'm putting it in the water in the morning. thanks for all the info and help.

 

[Paul Moir]

Re: 1973 4hp evinrude overheating

It's normal for the spark plugs to be burning hot. Also the flat exhaust plate since it's in the direct path of the exhaust gasses.

Good luck!